Pneumatic grain cleaner



April 5, 1960 I. K. ANDREN ET AL 2,931,500

PNEUMATIC GRAIN CLEANER Filed June 24, 1957 2 Sheets-Sheet 1 INVENTORSK. L. ANDRE/v 6. E R/DDERSTROM ATTORNEYS April 1960 l. K. L. ANDRENEI'AL 2,931,500

PNEUMATIC GRAIN CLEANER 2 sheets-sheet 2 Filed June 24, 1957 INVENTORSmm R 0.1 S R n mm A'I'TORNEYJ United States Patent PNEUMATIC GRAINCLEANER Ingmar Karl Linus Andrn and Gustav Folke Ingmar Ridderstriim,Lindesberg, Sweden, assignors' to Aktiebolaget Linde Maskiner,Lindesberg, Sweden, :1 corporation of Sweden Application June 24, 1957,Serial No. 667,336 Claims priority, application Sweden June 29, 1956 1Claim. (Cl. 209-139) The present invention relates broadly to thev artof cleaning machines, particularly those utilized for cleaning seed,grain and the like in which an air current is employed to effect thecleaning and to separate impurities such as husks and other particleslighter in weight than the particles being cleaned.

Thus, the invention relates to a seed or grain cleaner in which agaseous medium such as an air current is forced to flow in a givendirection and the material to be cleaned such as seed or grain isintroduced into the air current so that particles or impurities of lightweight are entrained in the air current and removed from the seed orgrain being cleaned, which due to its weight falls by gravity effectcounter current to the direction of flow of the air current.

It is, therefore, an object of the present invention to provide, in agrain or seed cleaning machine, a unique and simple arrangement of airchannels and a method of effecting separation of impurities from grainor seed to be cleaned which combines a simple and effective channelingof the separating air current to attain a maximum efficiency.

In grain cleaning machines in accordance with the invention, thevertically disposed or updraft air channels are for the most part ofrectangular or oval horizontal cross section and are so constructed asto width in their major dimension that a portion of the air currentflowing therethrough is not utilized for cleaning purposes but isexhausted in any suitable manner away from the cleaning machine so thatthe feed path of seed or grain to be cleaned has less transversedimensions than the air channel whereby more effective cleaning isobtained.

In grain cleaning machines utilizing what can be termed an updraft aircurrent, two general systems of establishing the air current are known,namely one in which a fan induces an air current through the channel bysuction and the other in which the fan, centrifugal blower of the likeis arranged below the path of fiow of the material to be cleaned so thatthe air current is blown through the said material. The air channels aregenerally constructed so as to be rectangular in cross section with theshort sides being only a fraction of the length of the long sides.Constructing channels in this form has the effect that if an air currentis blown or drawn by a fan through the channel, the air velocity is notthe same throughout the entire cross section of the channel. This isbecause skin friction in the ends of the channel adjacent the shortsides reduces air velocity in these portions of the channel. In otherwords, there is a large frictional resistance that the moving air has toovercome in the opposite ends of the channel and in the corn rs thereof,plus the fact that the impeller or fan usually has a smaller or narrowercommunication with the air channel so that it operates more effectivelyin the central portion of the channel than at the lateral edges.Therefore, in conventional cleaning machine constructions, wherein thegrain or seeds to be cleaned are fed fan means are located above thefeed means.

2,931,500 Patented Apr; 5, 1960 into the updraft air channel throughouta path coextensive in width with the width of the channel an unevencleaning action occurs.

It has been ascertained that in an updraft air channel construction fora grain cleaning machine having a channel or conduit measuring 1.5meters along its long side and .08 meter alongits short side that it isonly at a location at 0.2 meter inwards from the opposite short sidestoward the center of the channel that the air velocity attains the samevalue as exists in the central portion of the channel. Consequently,there is attained a uniform or even'suction or blast effect from a fanthrough the separating screen associated with such channel for an extentof only a section of 1.1 meters of the shafts total width of 1.5 meters.In other words, adjacent the corners of the air channel and the screenassociated therewith, the cleaning action is not as effective as it isin the mid portion of the air channel so that certain impurities ofintermediate weight can fall down with the cleaned grain, seed or thelike.

It is therefore an object of the invention to provide in a machine forcleaning grain or the like material a combination of wall means thatdefines an upwardly directed channel of uniform cross-sectional shapethroughout its effective extent and having major and minor dimensions,with the major dimension being substantially greater than the minordimension. The channel has an open lower end and fan means at leastcoextensive in width with the major dimension of the channel areprovided for establishing an upwardly flowing air current through thechannel. Feed means are located adjacent the lower open end forintroducing material to be cleaned and the Further,

' the feed means have an extent in a direction parallel to the majordimension of the channel at the location where the material beingintroduced comes under the influence of the air current that is lessthan the major dimension of the channel, so as to define opposite endswhich respectively terminate inwardly of the opposite narrow ends of thechannel a distance such that the respective opposite marginal edges ofthe stream of introduced material are within the cross-sectional area ofthe channel wherein due to the uniformity of the cross-sectional shapeof the channel and the width of the fan means there exists substantiallyuniform air velocity.

Further and more specific objects of the invention will be apparent fromthe following description taken in connection with the accompanyingdrawings in which:

Figure 1 is a diagrammatic view partly in side elevation and partly invertical section illustrating a vertically disposed or updraft airchannel having an open lower end and with a feed screen disposed beneaththe same and in which the air current is induced from the upper portionof the channel and the material to be cleaned having been screenedbefore its introduction into the air current,

Figure 2 is a top plan view of the arrangement of Figre 1 with a portionof this view constituting a horizontal section taken along line 22 ofFigure 1,

Figure 3 is a view similar to Figure l but illustrating an arrangementfor cleaning grain or a like material in which such material is fed intothe air channel from a bin and is screened after being air cleaned, and

Figure 4 is a top plan view of Figure 3 illustrating the extension ofthe air channel beyond the side edges of the screen and the feed bin.

As indicated above, the invention is not to be limited to arrangementsin which the grain or other material to be fed is introduced directlyinto the vertically disposed or updraft air channel of uniformcross-sectional shape intermediate the ends thereof. Thus, Figures 1 and2 ili V v 31932 lustrate an inclined screen S over which the material tobe screened and cleaned flows by gravity to pass beneath the open lowerend of a vertically disposed updraft air channel of rectangular formhaving its long walls A extending transversely of the screen anditsshort end walls B and C extending parallel to the lateral edges ofthe screen. As shown in Figure 2 the Width of the screen S is less thanthe distance between the end walls B and C of the air channel. Thescreen S is dimensioned and supported relative to the air channel sothat an equal area of air channel projects beyond the opposite sideedges of the screen. Suitable legs such as at L support the screen. Asuction fan means including a housing H and a fan F, which as shown inFigure 2 has a width coextensive with the extent of walls A,'isincorporated with an upper part of theair channel; The fan is driven byany suitable drive connected to pulley P. Asshown, the fanmeans islocated above the screen or feed means whereby in operation the grainpassing over the screen S is preliminarily screened so that smallerimpurities fall through the screen and unscreened material is thensubjected to the induced air current flowing upwardly through the airchannel. The spaces X and Y, Figure 2, at the opposite ends of the airchannel are those areas where the air velocity is lower than in theportion of the air channel overlying the screen. in that portion of theair channel overlying the screen the air velocity is uniform so thatlightweight impurities, that is, those lighter than the grain G to becleaned are drawn oil" through the air channel with the full extent ofthe flow of material moving along the screen being subjected to uniformair velocity for effective cleaning.

Figure 3 illustrates an arrangement in which a feed'bin Fe is attachedto one side wall A of the air channel, a roller D acts as a dischargeroller to discharge material G to be cleaned from the bin beneath thepartition 1'. The

material after passing over the roiler strlkesthe inclined bottom wallsof the bin and flows through a slot E in the wall A. The slot isdisposed. above the bottom of the vertically disposed air channel orconduit and the major dimensions of the channel are in excess of thescreen S and bin Pa. The material to be cleaned is subjected to aninduced air current by a fan means including a housing H and a fan F,driven by a suitable drive to a pulley P. The housing and fan areoperatively associated with the air channel similarly to therelationship of Figure l at a location above the bin so as to suck airupwardly through the open lower end of the air channel. The heavierparticles fall through the air stream and land on the screen 5 whereinany further small size though heavy impurities pass through the screenwhile the grain, seed or other material to be recovered flows down thescreen S for col ec E sure 4i st ates e ex sion a d Y of the air channelthat project beyond the opposite side walls of the bin Pe so that thewidth of the falling curtain of particles to be cleanedis restricted toan extent of the air channel that is intermediate the ends thereof,whereby the low air velocity chest that exists in areas X and Y are'n'otapplied to thecleaning or the material and the entire stream of materialis subjected to substantially uniform air velocity.

Whilein the" attached drawings the screen bin and updraft all channelsare rectangular in form, it is believed clear that other cross sectionalshapes are applicable, such as oval'a'ir channels and different shapedscreens and ia 9 le s as he. Pr p s of h nve n i c ing restricting thewidth of the path of flow of material to be cleaned to dimensions'les'sthan the major dimensions of the air channel along its inlet side isincluded.

What is claimed is:

In a machine for cleaning grain or the like material, the combination ofwith means defining an upwardly di rected channel of uniformcross-sectional shape throughout its effective extent and having majorand minor dimensions, with the major dimension being substantiallygreater than the minor dimension, said channel having an open lower end,fan means at least coextensive in width with the major dimension of thechannel for establishing an upwardly flowing air current therethrough,feed means adjacent the open lower end of the channel for introducingmaterial to be cleaned into said air current from a direction that istransverse of the major dimen-r sion of the channel, whereby lightweightparticles of material are conveyed upwardly through the channel, saidfan being above said means, and said feed means for introducing materialhaving an extent in a direction parallel to the major dimension of thechannel at the location where the material being introduced comes underthe influence of the air current that is less than the major dimensionof the channel, so as to define opposite ends which respectivelyterminate inwardly of the opposite narrow ends of the channel a distancesuch that the respective opposite marginal edges of the stream ofintroduced material are within the cross-sectional area of the channelwherein dueto the uniformity of the cross-sectional shape of the channeland the Width of the fan, there exists substantially uniform airvelocity.

